U.S. patent number 8,236,485 [Application Number 10/389,214] was granted by the patent office on 2012-08-07 for photoresist removal.
This patent grant is currently assigned to Advanced Technology Materials, Inc.. Invention is credited to Thomas H. Baum, David Daniel Bernhard, David W. Minsek, Melissa K. Murphy.
United States Patent |
8,236,485 |
Minsek , et al. |
August 7, 2012 |
Photoresist removal
Abstract
Disclosed herein is a composition and method for semiconductor
processing. In one embodiment, a wet-cleaning composition for
removal of photoresist is provided. The composition comprises a
strong base; an oxidant; and a polar solvent. In another
embodiment, a method for removing photoresist is provided. The
method comprises the steps of applying a wet-cleaning composition
comprising about 0.1 to about 30 weight percent strong base; about
one to about 30 weight percent oxidant; about 20 to about 95 weight
percent polar solvent; and removing the photoresist.
Inventors: |
Minsek; David W.
(Pleasantville, NY), Murphy; Melissa K. (Danbury, CT),
Bernhard; David Daniel (Newtown, CT), Baum; Thomas H.
(New Fairfield, CT) |
Assignee: |
Advanced Technology Materials,
Inc. (Danbury, CT)
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Family
ID: |
32684764 |
Appl.
No.: |
10/389,214 |
Filed: |
March 14, 2003 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20040180300 A1 |
Sep 16, 2004 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60434971 |
Dec 20, 2002 |
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Current U.S.
Class: |
430/329; 510/176;
438/906; 510/402; 510/503; 134/34; 134/1.3 |
Current CPC
Class: |
C11D
7/50 (20130101); C11D 3/3956 (20130101); C23G
1/20 (20130101); C11D 3/3947 (20130101); C11D
3/044 (20130101); C11D 7/06 (20130101); H01L
21/31133 (20130101); H01L 21/31116 (20130101); G03F
7/423 (20130101); C11D 11/0047 (20130101); C11D
3/43 (20130101); C11D 3/3955 (20130101); C11D
7/3209 (20130101); H01L 21/0206 (20130101); C11D
1/72 (20130101); G03F 7/425 (20130101); C11D
7/34 (20130101); C11D 7/3281 (20130101); C11D
3/30 (20130101); Y10S 438/906 (20130101); H01L
21/02052 (20130101) |
Current International
Class: |
G03F
7/42 (20060101); B08B 3/04 (20060101) |
Field of
Search: |
;430/329
;510/176,402,504 ;134/34,902 ;438/906 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0128014 |
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May 1984 |
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EP |
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1049141 |
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Nov 1999 |
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EP |
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9960448 |
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Nov 1999 |
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WO |
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Other References
US. Appl. No. 60/386,800, filed Jun. 7, 2002, Hsu. cited by other
.
European Patent Office, Supplementary European Search Report, Feb.
12, 2010. cited by other .
IBM J. Res. & Dev., v. 45, No. 5, Sep. 2001, "Dissolution
behavior of chemically amplified resist polymers for 248, 193-and
157-nm lithography". cited by other.
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Primary Examiner: Davis; Daborah Chacko
Attorney, Agent or Firm: Fuierer; Tristan A. Moore & Van
Allen, PLLC Yaghmour; Rosa
Parent Case Text
RELATED APPLICATION
This Application claims priority of U.S. Provisional App. Ser. No.
60/434,971, Filed Dec. 20, 2002.
Claims
We claim:
1. A cleaning solution comprising: a polar solvent; a base
rendering a pH of greater than about 11.5 to said solution; and an
amine-N-oxide, wherein said solution is useful for removing
post-etch photoresist residue from a semiconductor substrate having
same thereon.
2. The cleaning solution of claim 1 wherein said polar solvent
comprises between about 20% and about 95% of said solution by
weight.
3. The cleaning solution of claim 1 wherein said base comprises one
of ammonium hydroxide and tetramethyl ammonium hydroxide.
4. The cleaning solution of claim 3 wherein said base comprises
between about 0.1% and about 3.5% of said solution by weight.
5. The cleaning solution of claim 1 wherein said amine-N-oxide
comprises between about 1% and about 30% of said solution by
weight.
6. The cleaning solution of claim 1, wherein said polar solvent
comprises a polar species selected from the group consisting of
water, an alcohol, ethylene glycol, propylene glycol, glycol ethers
thereof, an amide, and a carbonate.
7. The cleaning solution of claim 1, wherein said base is a
nitrogen containing compound of the formula
(NR.sup.1R.sup.2R.sup.3R.sup.4).sup.+OH.sup.-, wherein R.sup.1,
R.sup.2, R.sup.3 and R.sup.4 are each one of hydrogen, alkyl or
substituted aryl groups.
8. The cleaning solution of claim 1, wherein said base comprises
tetramethylammonium hydroxide.
9. The cleaning solution of claim 1, wherein said amine-N-oxide has
the formula: ##STR00003## wherein R.sub.1 and R.sub.2 may be
hydrogen, methyl, further substituted or unsubstituted alkyl groups
or may form two ends of an alkyl chain, and R.sub.3 may be methyl,
further substituted or unsubstituted alkyl groups or may form two
ends of an alkyl chain.
10. The cleaning solution of claim 1, wherein said amine-N-oxide
comprises N-methylmorpholine-N-oxide.
11. The cleaning solution of claim 1, further comprising a species
selected from the group consisting of a co-solvent, a chelator, a
surfactant, and combinations thereof.
12. The cleaning solution of claim 11 wherein said co-solvent
comprises up to about 50% of said solution by weight.
13. The cleaning solution of claim 11 wherein said co-solvent is
one of an alkylamine, an alkanolamine, and a glycol.
14. The cleaning solution of claim 11 wherein said surfactant
comprises up to about 20% of said solution by weight.
15. The cleaning solution of claim 11 wherein said surfactant is
one of a fluoroalkyl, a glycol, a carboxylic acid salt,
dodecylbenzene sulfonic acid, a dodecylbenzene sulfonic acid salt,
a silicone polymer, a polyacrylate polymer, and acetylenic diol,
alkylammonium and alkylammonium salt.
16. The cleaning solution of claim 11 wherein said chelator
comprises up to about 10% of said solution by weight.
17. The cleaning solution of claim 11 wherein said chelator is one
of a triazole, a thiazole, a tetrazole, an imidizole, a phosphate,
a thiol, an azine, a glycerol, an amino acid, a carboxylic acid, an
alcohol, an amide, and a quinoline.
18. A method comprising: patterning a photoresist on a
semiconductor substrate; and cleaning the semiconductor substrate
with a cleaning solution, said cleaning solution: a polar solvent;
a base rendering a pH of greater than about 11.5 to said solution;
and amine-N-oxides, wherein said solution is useful for removing
residue resulting from a photoresist etching process.
19. A cleaning solution comprising: a polar solvent; a base
rendering a pH of greater than about 11.5 to said solution; and
N-methylmorpholine-N-oxide, wherein said solution is useful for
removing post-etch photoresist residue from a semiconductor
substrate having same thereon.
20. The cleaning solution of claim 19 wherein said polar solvent
comprises a polar species selected from the group consisting of
water, an alcohol, ethylene glycol, propylene glycol, glycol ethers
thereof, an amide, and a carbonate.
21. The cleaning solution of claim 19 wherein said base is a
nitrogen containing compound of the formula
(NR.sup.1R.sup.2R.sup.3R.sup.4).sup.+OH.sup.-, wherein R.sup.1,
R.sup.2, R.sup.3 and R.sup.4 are each one of hydrogen, alkyl or
substituted aryl groups.
22. The cleaning solution of claim 19 wherein said polar solvent
comprises between about 20% and about 95% of said solution by
weight.
23. The cleaning solution of claim 19 wherein said base comprises
one of ammonium hydroxide and tetramethyl ammonium hydroxide.
24. The cleaning solution of claim 19 further comprising a species
selected from the group consisting of a co-solvent, a chelator, a
surfactant, and combinations thereof.
25. A method to remove post-etching photoresist residue from a
semiconductor substrate comprising: forming a photoresist pattern
on a semiconductor substrate and etching same; and contacting the
semiconductor substrate with a cleaning solution according to claim
19, for a sufficient amount of time to effect substantial cleaning
of the semiconductor substrate.
Description
FIELD OF THE INVENTION
The present invention relates to semiconductor processing and, more
particularly, to photoresist removal.
BACKGROUND OF THE INVENTION
Integrated circuits are manufactured by a general sequence of steps
wherein photoresist is coated onto a substrate, the photoresist
layer is patterned by exposure and development, the pattern is
transferred to the substrate, and the photoresist removed. This
sequence of steps is repeated to build up multiple layers of
patterned circuitry. For the photoresist removal step, plasma
ashing is commonly used since etched photoresist residues may be
difficult or impossible to remove using only wet cleaning,
especially without damaging other materials that are present.
Positive photoresist is soluble in alkaline aqueous solutions as
well as in compositions consisting of select organic and inorganic
compounds. However, photoresist that has been exposed to a
gas-phase plasma etch, such as a gas-phase plasma etch used for
etching dielectric materials, will typically develop a hardened
crust or residue, on the surface. The residue typically consists of
cross-linked organic polymers, and may contain small amounts of
silicon, metal, and halogen or other atoms.
Damascene or dual damascene processes commonly utilize a plasma
etch such as that described above. The plasma etch may be a
fluorine-based plasma etch to etch silicate-based interlayer
dielectric (ILD) materials. These materials may include silicates,
organosilicates and fluorosilicates. Fluorine-based plasma etching
may cause fluorination of the cross-linked organic polymers that
form the residue described above. This fluorination typically
increases chemical resistance. Thus, the residue becomes difficult,
if not impossible, to remove by conventional wet stripping
techniques. Ashing using an oxidative or reductive plasma can
remove the residue. However, plasma ashing is prone to damage to
the ILD materials, especially low-k ILD materials.
Therefore, a need exists for photoresist removal that can remove
photoresist residue but does not damage the ILD materials.
SUMMARY OF THE INVENTION
Disclosed herein is a composition and method for semiconductor
processing. In one embodiment, a wet-cleaning composition for
removal of photoresist is provided. The composition comprises a
strong base; an oxidant; and a polar solvent. In another
embodiment, a method for removing photoresist is provided. The
method comprises the steps of (i) applying a wet-cleaning
composition comprising about 0.1 to about 30 weight percent strong
base, about one to about 30 weight percent oxidant, and about 20 to
about 95 weight percent polar solvent; and (ii) removing the
photoresist.
A more complete understanding of the present invention, as well as
further features and advantages of the present invention, will be
obtained by reference to the following detailed description and
drawings.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Disclosed herein is a composition and method for semiconductor
processing. According to one aspect of the invention, a
wet-cleaning composition for removal of photoresist is provided.
The composition includes a strong base. For example, the strong
base may yield a solution having a pH greater than about 11.5, even
where the strong base makes up no more than about 3.5% of the
solution. That is, the strong base may be no more than about 3.5
weight percent of the solution. However, as described further
herein, higher strong base concentrations may be desirable. The
strong base assists in the removal of the photoresist, e.g.,
unexposed positive photoresist. The composition also includes an
oxidant and a polar solvent. Strong bases of the formula I, shown
below, may be used in accordance with the teachings of the present
invention.
##STR00001## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each
one of hydrogen, alkyl or substituted alkyl groups. Suitable strong
bases include, but are not limited to, ammonium hydroxide,
tetramethylammonium hydroxide (TMAH), choline hydroxide, as well as
combinations comprising at least one of the foregoing strong bases.
In an exemplary embodiment, the strong base comprises
tetramethylammonium hydroxide.
The cleaning composition or solution described is particularly
useful for cleaning photoresist residue from a semiconductor
substrate. For example, in one embodiment, a semiconductor
substrate is patterned to form trenches therein. This is done in a
manner employing a photoresist. The photoresist and any residue may
be removed from the trench and substrate with the described
cleaning solution. A semiconductor feature such as a metal line may
be formed in the trench followed by chemical mechanical
planarazation to isolate the metal line. Further semiconductor
processing may follow to form a completed semiconductor device.
In an exemplary embodiment, the composition of the present
invention comprises greater than or equal to about 0.1 weight
percent strong base, with greater than or equal to about one weight
percent strong base preferred and greater than or equal to about
five weight percent strong base more preferred. In the exemplary
embodiment, the composition of the present invention further
comprises less than or equal to about 30 weight percent strong
base, with less than or equal to about 20 weight percent strong
base preferred and less than or equal to about ten weight percent
strong base more preferred.
The composition further comprises an oxidant. Suitable oxidants
include, but are not limited to, inorganic oxidizers, organic
oxidizers, e.g., amine-N-oxides, perborate salts, persulfate salts,
percarbonate salts, as well as combinations comprising at least one
of the foregoing oxidants. In an exemplary embodiment, the oxidant
comprises organic oxidizers. Organic oxidizers of the general
formula II, shown below, may be used in accordance with the
teachings of the present invention.
##STR00002## wherein R.sup.1, R.sup.2 and R.sup.3 may be hydrogen,
methyl or further substituted or unsubstituted alkyl groups.
R.sup.1 and R.sup.2 may form two ends of an alkyl chain.
While peroxides, e.g., hydrogen peroxide and substituted alkyl or
aryl peroxides, may be used in accordance with the teachings of the
present invention, amine-N-oxides have the advantage of being a
more mild oxidant as compared to the peroxides in general. Further,
amine-N-oxides decompose less rapidly as compared to peroxides in
general. In particular, it is well-known that hydrogen peroxide in
alkaline environments decomposes rapidly, yielding oxygen and
water, a condition that leads to a short bath life especially at
temperatures greater than ambient. Also, hydrogen peroxide may be
unstable in the presence of oxidizable organic species, for
example, amines and alcohols. Thus, in accordance with the
teachings of the present invention, a non-peroxide oxidant is
preferred.
In an exemplary embodiment, the composition of the present
invention comprises greater than or equal to about one weight
percent oxidant, with greater than or equal to about five weight
percent oxidant preferred and greater than or equal to about ten
weight percent oxidant more preferred. In the exemplary embodiment,
the composition of the present invention further comprises less
than or equal to about 30 weight percent oxidant, with less than or
equal to about 20 weight percent oxidant preferred and less than or
equal to about 15 weight percent oxidant more preferred.
The composition further comprises a polar solvent. The polar
solvent solubilizes ionic components both in the photoresist and in
the photoresist residues. Suitable polar solvent include, but are
not limited to, water, ethylene, propylene, other glycol solvents,
glycol ethers, alcohols, amides, carbonates, as well as
combinations comprising at least one of the foregoing polar
solvents. In an exemplary embodiment, the polar solvent comprises
water due to its low cost and non-toxicity.
In an exemplary embodiment, the composition of the present
invention comprises greater than or equal to about 20 weight
percent polar solvent, with greater than or equal to about 30
weight percent polar solvent preferred and greater than or equal to
about 40 weight percent polar solvent more preferred. In the
exemplary embodiment, the composition of the present invention
further comprises less than or equal to about 95 weight percent
polar solvent, with less than or equal to about 85 weight percent
polar solvent preferred and less than or equal to about 75 weight
percent polar solvent more preferred.
The composition may further comprise a chelator. Suitable chelators
include, but are not limited to, unsubstituted triazoles,
substituted triazoles, thiazoles, tetrazoles, imidazoles,
phosphates, thiols and azines, glycerols, amino acids, carboxylic
acids, alcohols, amides, quinolines, as well as combinations
comprising at least one of the foregoing chelators.
Unsubstituted triazoles include, but are not limited to,
1,2,3-triazole and 1,2,4-triazole. Further, triazoles may be
substituted with alkyl groups, amino groups, benzo groups, thiol
groups, mercapto groups, imino groups, carboxy groups, nitro
groups, as well as combinations comprising at least one of the
foregoing substituted groups. Substituted triazoles include, but
are not limited to benzotriazole, polyltriazole,
5-phenyl-benzotriazole, 5-nitro-benzotriazole,
1-amino-1,2,3-triazole, 1-amino-1,2,4-triazole,
1-amino-5-methyl-1,2,3-triazole,
hydroxybenzotriazole,2-(5-amino-pentyl)-benzotriazole,
3-amino-1,2,4-triazole,3-isopropyl-1 ,2,4-triazole,
3-mercapto-1,2,4-triazole, 5-phenylthiol-benzotriazole,
halo-benzotriazoles, napthotriazole. Thiazoles, tetrazoles,
imidazoles, phosphates, thiols and azines include, but are not
limited to, 2-mercaptobenzoimidizole, 2-mercaptobenzothiazole,
5-aminotetrazole, 5-amino-1,3,4-triadiazole-2-thiol, thiazole,
triazine, methyltetrazole, 1,3-dimethyl-2-imidazolidinone,
1,5-pentamethylenetetrazole, 1-phenyl-5-mercaptotetrazole,
diaminomethyltriazine, mercaptobenzothiazole, imidazoline thione,
mercaptobenzoimidazole, 4-methyl-4H-1,2,4-triazole-3-thiol,
benzothiazole, tritolyl phosphate, indiazole, as well as
combinations comprising at least one of the foregoing. Glycerols,
amino acids, carboxylic acids, alcohols, amides, quinolines
include, but are not limited to, guanine, adenine, glycerol,
thioglycerol, nitrilotriacetic acid, salicylamide, iminodiacetic
acid, benzoguanamine, melamine, thiocyranuric acid, anthranilic
acid, 8-hydroxyquinoline, 5-carboxylic acid-benzotriazole,
3-mercaptopropanol, boric acid and iminodiacetic acid.
The chelator may be added to the composition to prevent the etching
or corrosion of metal surfaces, e.g., copper, tungsten, aluminum
and alloys thereof, exposed to the composition. As such, the
chelator may be used to increase the compatibility of the
composition with the metals and dielectric materials used in the
semiconductor device.
In an exemplary embodiment, the composition of the present
invention comprises less than or equal to about ten weight percent
chelator, with less than or equal to about seven weight percent
chelator preferred and less than or equal to about four weight
percent chelator more preferred.
The composition may further comprise a co-solvent. The co-solvent
may be added to improve compositional properties, namely the
ability of the composition to swell, dissolve, and lift off
photoresist residues. Suitable co-solvents include, but are not
limited to, substituted alkylamines or alkanolamines such as
N,N-dimethyldiglycolamine, 1,8-diazabicyclo[5.4.0]undecene,
aminopropylmorpholine, triethanolamine, methylethanolamine, glycol
solvents such as ethylene glycol, diethylene glycol, propylene
glycol, neopentyl glycol, glycol ethers such as di(ethylene
glycol)monoethyl ether, di(propylene glycol)propyl ether, ethylene
glycol phenyl ether, di(propylene glycol)butyl ether, butyl
carbitol, polyglycol ethers, as well as combinations comprising at
least one of the foregoing co-solvents.
Further, the co-solvent should be polar. A polar compound will
remain miscible with the polar solvent and will keep ionic species
such as tetramethylammonium hydroxide dissolved. In an exemplary
embodiment, the composition of the present invention comprises less
than or equal to about 50 weight percent co-solvent, with less than
or equal to about 30 weight percent co-solvent preferred and less
than or equal to about 20 weight percent co-solvent more
preferred.
The composition may further comprise a surfactant. The surfactant
may be added in order to assist in both the lifting-off of
insoluble photoresist residues and reduce silicon etching, which
may occur under exposure to strong bases. Suitable surfactants
include, but are not limited to, anionic, cationic, nonionic
surfactants, such as fluoroalkyl surfactants, polyethylene glycols,
polypropylene glycols, polyethylene or polypropylene glycol ethers,
carboxylic acid salts, dodecylbenzenesulfonic acid or salts
thereof, polyacrylate polymers, silicone or modified silicone
polymers, acetylenic diols or modified acetylenic diols,
alkylammonium or modified alkylammonium salts, as well as
combinations comprising at least one of the foregoing
surfactants.
In an exemplary embodiment, the composition of the present
invention comprises less than or equal to about 20 weight percent
surfactant, with less than or equal to about 15 weight percent
surfactant preferred and less than or equal to about ten weight
percent surfactant more preferred.
Another aspect of the invention provides a method for removing
photoresist. The method comprises the steps of applying a
wet-cleaning composition comprising about 0.1 to about 30 weight
percent strong base; about one to about 30 weight percent oxidant;
and about 20 to about 95 weight percent polar solvent; and removing
the photoresist.
The term photoresist as used herein is generally applicable to any
layer comprising photoresist. Thus, for example, in accordance with
the teachings of the present invention, the composition and method
herein may be used to remove photoresist as well as photoresist
residue. Additionally, the teachings of the present invention apply
to the removal of any photoresist residue, i.e., resulting from an
etching process including, but not limited to, fluorine-based
plasma etching.
Although illustrative embodiments of the present invention have
been described herein, it is to be understood that the invention is
not limited to those precise embodiments, and that various other
changes and modifications may be effected therein by one skilled in
the art without departing from the scope or spirit of the
invention. The following examples are provided to illustrate the
scope and spirit of the present invention. Because these examples
are given for illustrative purposes only, the invention embodied
therein should not be limited thereto.
EXAMPLES
The following formulations produced substantial cleaning of
photoresist from a semiconductor substrate. Substantial cleaning,
according to the teachings of the present invention, is defined as
being greater than 80 percent removal of the photoresist from the
semiconductor device, and may be determined by optical and electron
microscopy. The substrate employed herein consisted of chemically
amplified photoresist coated onto an orgariosilicate dielectric
coated silicon wafer. Additionally, the photoresist was exposed to
patterned radiation and developed, and the pattern was then
transferred to the dielectric by a plasma etch.
Example 1
Composition A was prepared as follows:
TABLE-US-00001 Composition A Component Weight Percent
N-Methylmorpholine-N-oxide (50 weight 13.5 percent solution) TMAH
(25 weight percent solution) 7.3 Water 79.2
The N-methylmorpholine-N-oxide was supplied and used as a 50 weight
percent solution, and tetramethylammonium hydroxide (TMAH) was
supplied and used as a 25 weight percent solution in the present
example, as well as in further examples employing
N-methylmorpholine-N-oxide and tetramethylammonium hydroxide
(TMAH).
A photoresist substrate was cleaned by immersion in composition A
for 20 minutes at 70.degree. C. All of the photoresist and etch
residues were removed from the substrates as observed by optical
and electron microscopy. Significant etching of the dielectric
material was not observed.
Example 2
Compositions B, C and D were prepared, each containing 13.5 weight
percent N-Methylmorpholine-N-oxide, 7.3 weight percent TMAH, 78.9
weight percent water and 0.3 weight percent of the inhibitor
2-mercaptobenzimidazole (2-MBI) as shown below. 2-MBI was included
in the formulation in order to retard etching of copper or other
metals by the solution, as may be seen in Example 3.
TABLE-US-00002 Composition Additive B
2,4-Diamino-6-methyl-1,3,5-triazine C
5-Amino-1,3,4-thiadiazole-2-thiol D 2-Mercaptobenzimidizole
Photoresist substrates were cleaned by immersion in the stripper
for 20 minutes at 70.degree. C.
Example 3
Etch rates of a blanket coating of copper (Cu) on a silicon wafer
were measured using compositions A through D, as prepared above.
The copper layer was deposited by physical vapor deposition and was
about 1000 angstroms (.ANG.) in thickness. Samples were immersed in
the composition for a fixed time, and the thickness was measured
both before and after using four-point probe electrical
measurements. Etch rates were calculated by dividing the difference
in thickness, i.e., the thickness before etching, less the
thickness after etching, by the time in minutes. The etch rates for
compositions A through D are given below.
TABLE-US-00003 Cu Etch Rate at Composition 70.degree. C.
(.ANG./min) A 15.8 B 1.5 C 3.2 D 1.1
Example 4
Composition E was prepared as follows:
TABLE-US-00004 Composition E Component Weight Percent
N-Methylmorpholine-N-oxide (50 weight 13.5 percent solution) TMAH
(25 weight percent solution) 7.5 2-Mercaptobenzimidizole 0.08 Water
64.1 N,N-Dimethyldiglycolamine 15.0 polyethyleneglycol
4-nonylphenyl ether 0.05
Polyethyleneglycol 4-nonylphenyl ether is a surfactant containing
about 5 ethyleneglycol repeat units. After immersion in Composition
E for 15 minutes at 70.degree. C., there was 100 percent
photoresist residue removal from all areas of the
semiconductor.
Example 5
Composition F was prepared as follows:
TABLE-US-00005 Composition F Component Weight Percent
N-Methylmorpholine-N-oxide (50 weight 13.5 percent solution) TMAH
(25 weight percent solution) 6.5 2-Mercaptobenzimidizole 0.01 Water
76.09 Non-ionic fluorosurfactant 0.1
The potential etching effects of compositions A and F on
polysilicon were determined by immersing 1000 .ANG. wafer sections
of polysilicon on silicon, in each composition, for 15 minutes at
70.degree. C. Composition F showed no observable etching or
roughening of the polysilicon surface. Composition A did show
slight observable roughening of the polysilicon surface.
Example 6
Composition G was prepared as follows:
TABLE-US-00006 Composition G Component Weight Percent
N-Methylmorpholine-N-oxide (50 weight 13.5 percent solution) TMAH
(25 weight percent solution) 6.5 2-Mercaptobenzimidizole 0.01 Water
79.9 modified acetylenic diol surfactant 0.1
A photoresist substrate was cleaned by immersion in composition G
for 20 minutes at 70.degree. C. All of the photoresist and etch
residues were removed from the substrates, as observed by optical
and electron microscopy. However, etching or roughening of
polysilicon was observed under the same conditions.
Example 7
Composition H was prepared as follows:
TABLE-US-00007 Composition H Component Weight Percent
N-Methylmorpholine-N-oxide (50 13.5 weight percent solution) TMAH
(25 weight percent 3.5 solution) 2-Mercaptobenzimidizole 0.01 Water
82.89 2,4,7,9-tetramethyl-5-decyne-4,7-diol 0.1
A polysilicon coated wafer, as described in Example 5, did not show
observable etching or roughening when immersed in composition H for
15 minutes at 70.degree. C. However, Composition H failed to remove
the bulk of the photoresist crust from the substrate.
Example 8
Composition I was prepared as follows:
TABLE-US-00008 Composition I Component Weight Percent
N-Methylmorpholine-N-oxide (50 weight 13.5 percent solution) TMAH
(25 weight percent solution) 7.3 2-Mercaptobenzimidizole 0.2 Water
43.9 Non-ionic fluorosurfactant 0.1 Butyl carbitol 5
N,N-Dimethyldiglycolamine amine 15 1,8-diazabicyclo [5.4.0]
undecene 15
Use of composition I showed removal of the photoresist with
moderate protection of the polysilicon. Some etching or roughening
was exhibited when the polysilicon was immersed in the sample for
15 minutes at 70.degree. C. The copper etch rate remained low at
0.15 .ANG./minute and the tungsten etch rate was 0.67 .ANG./minute.
The copper and tungsten samples were immersed for 40 minutes at
70.degree. C.
Example 9
Composition J was prepared as follows:
TABLE-US-00009 Composition J Component Weight Percent
N-Methylmorpholine-N-oxide (50 weight 13.5 percent solution) TMAH
(25 weight percent solution) 7.3 2-Mercaptobenzimidizole 0.2 Water
49 Pentamethyldiethylenetriamine 30
Composition J resulted in complete removal of photoresist and
residues from the trench features and about 40 percent photoresist
residue removal from the bond pad area. The trench features
consisted of 1:1 line/space pairs of about 0.2 micron dimension,
and the bond pad areas consisted of a square array of square dummy
features of about 2 microns dimension.
Example 10
Composition K was prepared as follows:
TABLE-US-00010 Composition K Component Weight Percent
N-Methylmorpholine-N-oxide (50 weight 13.5 percent solution) TMAH
(25 weight percent solution) 7.3 2-Mercaptobenzimidizole 0.2 Water
58.0 Pentamethyldiethylenetriamine 20.0 Boric Acid 1.0
Composition K resulted in some residual photoresist on the trench
features with five percent of the bond pad area cleaned with
immersion in composition K for 20 minutes at 70.degree. C.
Example 11
Composition L was prepared as follows:
TABLE-US-00011 Composition L Component Weight Percent
N-Methylmorpholine-N-oxide (50 weight 13.5 percent solution) TMAH
(25 weight percent solution) 7.3 2-Mercaptobenzimidizole 0.2 Water
49.0 N-(3-Aminopropyl)-morpholine 30.0
Composition L resulted in complete photoresist removal from the
trench features and greater than 99.9 percent removal from the bond
pad area when immersed for 16 minutes at 70.degree. C.
Example 12
Composition M was prepared as follows:
TABLE-US-00012 Composition M Component Weight Percent
N-Methylmorpholine-N-oxide (50 weight 13.5 percent solution) TMAH
(25 weight percent solution) 7.3 2-Mercaptobenzimidizole 0.2 Water
49.0 N-Hydroxyethylmorpholine 30.0
Composition M resulted in ten percent photoresist removal in the
trench features and zero percent in the bond pad area when immersed
for 16 minutes at 70.degree. C.
Example 13
Composition N was prepared as follows:
TABLE-US-00013 Composition N Component Weight Percent
N-Methylmorpholine-N-oxide (50 weight 13.5 percent solution) TMAH
(25 weight percent solution) 7.3 2-Mercaptobenzimidizole 0.08 Water
64.1 N,N-Dimethyldiglycolamine amine 15.0
Composition N resulted in complete photoresist crust removal from
the trench features and 95 percent photoresist removal from the
bond pad areas when immersed for 20 minutes at 70.degree. C.
Example 13
Composition O was prepared as follows:
TABLE-US-00014 Composition O Component Weight Percent
N-Methylmorpholine-N-oxide (50 weight 12.6 percent solution) TMAH
(25 weight percent solution) 11.7 2-Mercaptobenzimidizole 0.08
Water 75.3 Polyethyleneglycol dinonylphenyl ether 0.3
Polyethyleneglycol dinonylphenyl ether is a surfactant containing
about 150 ethyleneglycol repeat units. Composition O resulted in
complete photoresist crust removal from the trench features and
complete percent photoresist removal from the bond pad areas when
immersed for 20 minutes at 70.degree. C.
Comparative Example 1
Comparative composition I consisted of ten weight percent
hydroxylamine, ten weight percent water and 80 weight percent
diglycolamine. Etched photoresist substrates were immersed in the
composition for 30, 50 and 60 minutes at 70.degree. C., followed by
a rinsing with water. Inspection by optical and electron microscopy
revealed that comparative composition I dissolved photoresist from
under the top layer of photoresist residue, but left the layer of
residue collapsed and attached to the samples in all regions.
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